MAX IV is the Swedish National Synchrotron Radiation facility in Lund. There are two storage rings at MAX IV, and both are designed to store 500-mA electron current. For the bigger 3-GeV ring, this 500mA current has not yet been achieved. To achieve this current, a more powerful RF system with a new automatic low-level control is needed. The MAX-IV RF team has defined the control unit characteristics as to be able to regulate the power in the range of three orders of magnitude and with an accuracy of better than 1%.  In the frames of the current work, a prototype for such a control unit has been built using an FPGA board and a PID regulator programmed in HDL. For its performance tests, a model RF system with two amplification “branches” reproducing the main features of the real RF system at MAX-IV has been designed, assembled, and put into operation. In a computer simulation, the theoretical performance of this model RF system has been characterized using the available and measured S-parameters of the circuit components. The measurements with the control unit steering the model system demonstrated the capability of adjusting the power of one amplification branch to the other within 1dBm (~1% power provided by each amplifier) and in the dynamic range of 30dB. Such properties of the control system not only allow a balanced functioning of a two-amplifier-based RF system but guarantee its safe operation when one of the amplifiers fully malfunctions. The chosen technical solution involving FPGA makes RF power regulation fast, software-free, flexible, precise, compact, and energy-saving. The balanced operation automatically minimizes energy losses and thus makes it possible to reach the 500-mA electron-current goal without over-dimensioning the amplification stages. Such electron current in the 3GeV opens new research opportunities for Swedish and international scientists working on new medicine, novel batteries and solar cells, catalysis and atmospheric chemistry.